Stability is the control of the body in movement using the neuromuscular system, resisting an undesired movement. Motor control is essential for stability. Without motor control there is no stability. The central nervous system (CNS) and the musculoskeletal system have to work in tandem to achieve the desired result of maintaining stability throughout the body. Stability is task-dependent; the stability required depends on the external stimulus. Stabilizing the body depends on the force required to stabilize the body under its own weight or that of an external load. Body position also affects stability; a narrower base of support is less stable than a wide one. Points of contact with the ground work in the same way; more contact has more support when compared to fewer points equaling less support. The motor control of muscles is actively stability.

Contents

Definitions

Motor control is the process wherein people use their neuromuscular system to move the body through space (Rosenbaum, D. 1991).

Stability: is the resisting of an undesired movement.

Mobility: creating a desired movement (Cook, G. 2012)

Development

What are children lacking? What stops them from standing up at a young age? Their lack of stability.

They cannot support their weight, specifically their disproportionately large heads. Children lack stability/motor control, but are abundant in mobility. As we age, we develop the muscles needed for motor control, typically at the expense of mobility. Stability is crucial in the development of motor patterns. A child will not be able to walk, run, jump, throw, or even raise their head without the requisite motor control. Acquiring stability is a fundamental attribute necessary for proper development.

Stability – Mobility Continuum

Stability and mobility are complementary in nature. Stability can’t exist without mobility and vice-versa. When you strive to make a joint more mobile you sacrifice stability. The reverse is also true, when you make a more stable joint, you lose mobility.

It’s a continuum with stability on one end and mobility at the other. For example the gleno-humeral joint would fall at the mobility end while the knee joint would require more stability. An example of a joint falling in the middle of the continuum would be the scapula. There is a need to balance stability and mobility through the body (Cook, G. 2012).

Kinetic chain/Joint by Joint Approach

Each joint requires either stability or mobility. From the ground up the foot requires stability while the ankle joint requires mobility. The knee joint is designed for stability, mobility at the hip joint, lumbar stability, thoracic mobility, Scapular stability, Gleno-Humeral mobility, elbow stability, wrist mobility, and hand stability. This isn’t black and white however, as it’s more accurate to think of it as mobility joints simply have more freedom of movement when compared to stability joints. All joints need some degree of stability and some degree of mobility. The Implications of this chain give great insight towards potential injury (Cook, G. 2012).

When a joint intended for stability is excessively mobile, it is at a greater risk for injury. This kinetic chain means that the actions of one joint impact all the others in the chain. The easiest example is the chain in the leg, if the ankle is injured the body will restrict movement as a protective mechanism (Cook, G. 2012). If mobility at the ankle is missing, it needs to be compensated for somewhere along the chain. Typically the issues at one joint can manifest upstream and downstream. If the ankle is less mobile due to stiffness the knee and foot will have to compensate by becoming more mobile. A mobile knee is at a much greater risk for injury. A mobile knee may mean the hip starts to tighten up which may make the lumbar spine less stable, and so on. The kinetic chain is called as such for a reason.

Joint Stability

The ability of musculoskeletal tissues to resist movement around a joint. Passive, active, and neural subsystems ensure the stability of a joint (Panjabi, M. 1992). Passive stability would come from the ligaments and tendons, active stability is generated my muscular tissues, and neural tone.

Core Stability

This refers to the muscles of the abdominal wall, pelvis, low back, and diaphragm. In essence the stability of the torso, since core could be interpreted as everything below your chin. The muscles of the diaphragm are directly involved in breathing, which is quintessential for providing stability necessary in movement. The ability to be stable through this area provides support and protection to the stability inclined lumbar spine. Any movement, specifically a loaded one, is accompanied by this generation of stability through the core. Bracing is necessary to hold tension and ensure trunk stability. This stability is required to create movement. The greater the demands of the movement, the greater tension required. A heavier load being lifted would require a greater level of stability and bracing through the abdomen. During a throw too much stiffness will limit the movement of the torso, limiting the explosiveness of the trunk and the velocity of the throw (McGill, S., et al. 2009). Though if there were no bracing during this movement it would be weak and uncoordinated. Without this protective tension the body is susceptible to injury. Being able to hold tension through the abdomen/torso is an important skill. It has a particular carry over to contact sports which essentially require athletes to maintain tension and move a load, typically another athlete’s body. Training core stability is a contended topic. Being able to breathe diaphragmatically, or bracing, is one method of creating tension through your core. Movement through this segment doesn't correlate with its purpose. Creating the tension, similar to that found, during a plank position is the same when standing. It is important to note that the “core” needs stability since it is the region responsible for the stability joint, the lumbar spine. Low back pain is often a result of a lack of stability and unnecessary mobility in the lumbar (McGill, S. 2007). This can be a result of missing hip mobility.

Benefits

Being able to support your own body weight, along with the ability to generate movements in objects with load. Being able to achieve simple movements requires stability. Baseline stability is needed to perform fundamental movement skills. Stability is holding the body in stable positions. Being in a stable position means that you are less likely to succumb to external forces into an undesirable position. By staying out of compromised positions injuries are prevented. Stability, in conjunction with mobility, prevents injury.

Common Problems

Stability as a compensation for lack of mobility, stiffness is not stability. Lacking motor control means that a whole host of movements are unachievable.

Practical Application

There are many ways to increase stability. The key is being able to have control of the body’s motor systems. This means that young children have to develop stability to acquire their movement skills. They must be stable enough to support themselves in all stages of development. Babies need to be stable enough to reach motor milestones like creeping, crawling, standing, walking, etc. When looking to develop stability different approaches can be taken. The correct one is a matter of opinion, though increasing motor control in the body through training seems optimal. Holding trunk stability such as in a plank clears an individual for the ability to be able to create tension in most other movements.